The 2011 earthquake and tsunami in Japan caused a meltdown at Fukushima nuclear power plant. This paper examines the association between demographics or exposure to potentially upsetting events following Fukushima disaster and psychological and physical well-being of mothers with young children 2 years after the Fukushima nuclear accident. The sample consisted of mothers with preschool children still inhabiting in low level radiation contamination area, 30~90 km distant from the plant. In addition to exposure status, the questionnaire obtained data on radiation anxiety, coping behavior, perceived economic stress and stress moderators. The dependent variables were measured by the K6, SQD (Screening Questionnaire for Disaster Mental Health).Overall, mental health of mothers with young children have been polarized as time passes. The conflict about coping behavior to radiation risk and economic stress increased the vulnerability of mothers to subsequent distress, PTSD, depression. It was confirmed a husband's childcare participation as a stress moderator. Longterm follow-up study is needed to confirm that the progress of mental health of mothers with young children.